<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <script>
        function show(){
            var oo=document.documentElement;
          //  alert(oo.innerHTML)
            var oh=oo.childNodes[0];
          //  alert(oh.innerHTML);
            var ob=document.body;
            alert(ob.innerHTML);
        }

    </script>
</head>
<body>
<div id="d1">a</div>
<div>b</div>
<div>c</div>
<a href="dom/node1.html">node1</a>
<a href="dom/node2.html">node2</a>
<a href="dom/node3.html">node3</a>
<a href="dom/node4.html">node4</a>
<a href="dom/node5.html">node5</a>

<button onclick="show()">显示</button>
</body>

</html>